Nail driving apparatus



Feb. 21, 3 1950 R, PAPALIA 2,498,503

I NAIL DRIVING APPARATUS Filed May 9, 1945 ,4 Sheets-Sheet l 2&4 /7Za/ "'24 ze; 268 we 7/2 /7 /75 v 7:

L g i f INVENTOR W6 7 am /26 JPOFCO pa/zgaahu BY I 7/2 ATTORNEYS Feb 21, 1950 Filed May 9, 1945 R. PAPALIA NAIL DRIVING APPARATUS 74 INVENTOR Papa/ha 4 Sheets-Sheet 2 J23? 13 W Mm ATTORNEYS Feb. 21, 1950 R. PAPALIA NAIL DRIVING APPARATUS 4 Sheets-Sheet 3 Filed May 9, 1945 INVENTOR V [P0060 Papaha BY we ATTORNEYS R. PAPALIA NAIL DRIVING APPARATUS Feb 21, 1950 4 Sheets-Sheet 4 Filed may 9), 1945 ,'W a 4 .1 13 2 4 m V 0m R E V M m m m V N 0 E v n N 0 A I C U 0 FY B QQ .WV\

Patented Feb. 21 1950 UNITED *sTATEs PATENT OFFICE NAIL DRIVING APPARATUS Rocco Papalia, Bridgeport, Conn.

Application May 9, 1945, Serial No. 592,737

29 Claims.

This invention relates to nailing machines, and more particularly to semi-automatic, powerdriven, portable nailing machines.

Heretofore, in building construction where wooden beams, studs, siding and the like were to be assembled by nailing, the common procedure was to fit the members in place, usually holding them with one hand, while the nailing was done by a hammer which was swung with the other hand. This procedure was generally tiresome and time-consuming, and slowed considerably the erection of the structure.

An object of the present invention is to obviate the disadvantages of this erection procedure as practiced in constructing structural forms, buildings and the like. This is accomplished by the provision of a highly efficient, conveniently operative, automatic nailing machine wherein a large number of nails may be quickly and accurately driven in succession into beams, siding, sheathing and the like, all with a minimum of skill and effort being required on the part of a workman. The nailing machine as provided by the invention comprises a hopper wherein a large quantity of nails may be deposited, and comprises a feeding means associated with the hopper for feeding nails therefrom one at a time for driving into the work, and also comprises portable hammering tools of light and compact design which may be easily held and manipulated by a workman, and may be applied in any position to the work, even where space is constricted, the hammering tools being flexibly connected with the hopper and feed mechanism so that nails may be automatically conveyed to it to replace the nails driven into the work. The hopper and feeding mechanism is so arranged that it may feed nails equally well to more than one hammering tool as a result of which several workmen may use the machine simultaneously to nail work in different places, all of the nails for the operations being supplied from the one hopper. The flexible connections between the hammering tools and the hopper and feed mechanisms may be of substantial length, so that the range or area covered by the machine is considerable for any given position of the hopper. The hammering tools may be operated simultaneously or singly as desired, the machine therefore being flexible in its operation.

Another object of the invention is to provide a powered automatic nailing machine which is safe in use, so that the likelihood of workers becoming inadvertently injured is considerably minimized. It is important that with a machine provided since the hammering tools are somewhat of the nature of guns from which the nails, acting as missiles, may be ejected under considerable velocity. If these nails were ejected into space, they could strike a worker either directly or by rebound and cause severe personal injury. By the present invention inadvertent ejection of the nails from the hammering tools when the latter are not being applied to workpieces is prevented by a safety device which automatically looks or makes inoperative the hammering means. However, when the hammering tool is applied to a workpiece preparatory to driving a nail therein, the safety device is automatically operated so that the hammering means may be made operative, and may then strike repeated blows to drive in the nail.

Yet another object of the present invention is to provide a powered automatic portable nailing device wherein, when a nail has been driven home, the hammering is automatically discontinued, and may not be again started to further drive the same nail. Thus, all of the nails will be driven home to the proper depth, and will not be overdriven or inadvertently countersunk, nor will they be underdriven. In accomplishing this the hammering tool is so organized that when the reciprocating hammering attains a certain advanced position it will be automatically deenergized even though the control means for the hammer is maintained in operative position. When, however, the control means is released, a new nail is automatically presented to the hammer, and subsequent operation of the control means will then again energize the hammer and cause it to operate.

Still another object of the invention is to provide a nailing machine having a hammering tool flexibly connected with a hopper, wherein the likelihood of jams occurring in the flexible conveying means between the tool and the hopper is minimized. As a result, the loss of time which would be occasioned by locating jams and freeing the same is practically eliminated, resulting in much higher production in a given period of time. The flexible connection between the hopper feed mechanism and the hammering tool, in the embodiment of the invention illustrated herein, comprises a flexible tube through which the nails are fed end to end preferably points foremost. Means are provided for rotating this tube so that the movement of the nails therethrough is facilitated, and so that the possibility of a nail catching on the inside of the tube is eliminated.

of the present type special safety means be v A still further object of the invention is to provide an improved hopper and feed mechanism whereby elongate articles such as nails, rivets and the like may be fed, by force and with a positive action, to the applicator or hammering tool. By thus dispensing with a feed wherein reliance is solely placed on gravity, the delivery of the nails to the hammering tool is made positive and effective.

A feature of the invention is that the positive mechanism of the machine is made to operate through buta single complete feeding cycle in response to the actuation of the hammering tool to drive in a nail, and the mechanism is automatically halted or made inoperative until the next nail of the hammering tool is being started in the work. The feed mechanism respondstoactuation of a manually operable trigger of the hammering tool, as the latter is depressed during the naildriving operation. The control for the feeding mechanism is such that the single cycle of operation will not. be repeated regardless of how' long the trigger is held in or. depressed, and if the trigger should be inadvertently released after the cyclehas once been initiated and before the hammering. is completed,. the cycle will stillbe carried to completion.

Another feature of the invention is the timing of, the. rotation .of the flexible nail-conveying tube, so that the latter turns only periodically and only when nails. are. being, f d: through the tube. reducesthe power required to operate the machine, and reduces. wear on the flexible tube, and the bearings for. thelatter.

Still. anotherfeature of the invention is the provision, in a power-driven, automatic portable hammering tool fed froma remote hopper, of a single manually operable member which. takes care of. the operations of positioning the nails one. by one in front of the hammer, controlling the operation: of the latter, and also controlling the; forced-feed to the hammering tool. as well as. the" rotation of the conveying tube, all automatically and in proper sequence without requiring attention on the part of. the workman. The manually:operableymember of the tool, which is inathe form of a. trigger, is reciprocally movable between: off? andv on positions: To operate the various parts. of. the nailing machine all that-is required of aworkman is merely topressthe trige gel and; release it. These. movements will. then automatically coordinate; the operations of the machinato. deliver and drive; nails into the. work at; any. pointv where the hammering tool is applied: under the. direction of. the workman. In the: embodiment of the invention illustrated herein, when the trigger is depressed the'hammer is. caused: to. become: operative to drive into the workama-ilrwhich has already been properly positionedior. driving. Also, the force-feed mechanism of; the machine is. actuated to deliver an.- other nail tothe hammering tool, to makeup for the nail being, driven into the work. When the;nail.has been driven home, the hammer automatically becomes inoperative. Upon release of thetrig er', thev hammer is retracted to. its start.- ing: position and av newnail is presented: in front of: the. hammer preparatory to the next driving operation. Since; all these operations 21.191031- riedout. automatically by merely depressing and releasing the trigger, no skill or thought is requireds on the part of the workman to use the machine. A feature. of the automaticcontrol as thusv effected bythe trigger movement is that; upon release: of. the. trigger after driving in a nail; and when. thehammering tool; has beenre- This positioned to a new place on the work by the workman, a new nail is already in position to be driven and the mere act of depressing the trigger immediately causes the hammer to become operative to drive in the new nail. Thus no time is taken up after repositioning of the hammering tool with any operations such as feeding or positioning the nails, before the hammer may be made'operative.

Still another feature of the invention is the provision of an automatic; power-drivenhammering tool of portable and compact design wherein, during the initial driving of a nail, the shank of the latter is supported to prevent its bending. As a result, the likelihood of nails becoming bent in the tool and jamming the mechanism thereof is obviated to a great extent.

A further feature of the invention resides in the: simplicity of construction and ease of manufacture of the hammering machine as outlined above.

Other features and advantages will hereinafter appear.

In the accompanying drawings Figure 1 is an elevational view of the nailing machine. of the. invention, shown in reduced scale.

Fig. 2 is a. fragmentary plan View of the machine, showingthe nail hopper and feed mechanisms on a slightly larger scale.

Fig. 3 is. a front elevation of the nail hopper and feed mechanisms of Fig; 2..

Fig. 4 is a detail (further enlarged) showing in vertical section: the right-handv magazine: of the feed mechanism. of Figs. 2'and 3, andshowing in elevation. a circuit control device for the feed mechanism.

Fig. 5 is a section taken on: the line 5-5 of Fig.4.

Fig. 6- is a detail showingin vertical section the lower portion of the left-hand magazine of the feedmechanism, and showing. the: nail transfer device between the magazine and the nail conveying tube.

Fig. 7 is a fragmentary section taken on the Iine'I- L of Fig. 4;

Fig. 8 is: an axial section taken through the hammering tool of. the machine;-

Fig. 9" is' afront or head-on elevation of the hammeringtool.

Fig. 1-0 is a part-elevation part-section taken on thelineill-400i Fig. 8.

Fig.v 11-. is a. part-section part-elevation taken ontheline-H-l l of Fig.8:

Fig- 1 2: is-asection taken on theline IZ-l'Z of Fig. 8;

, Fig; 13 is a section'taken on the:line l3'-l3 of Fig. 8;.

Fig..14 is a section takenon the line [4-4-4 of Fig..l3.

Fig. 15. isadetai1, in. elevation, of. another part of thecircuit control device for thefeed mechanism shown in Fig, 4.

Fig. 16.- is. adetail showing the circuit control device. for the feed mechanisms.- in side. elevation: on areducedscale.

Fig. 17' isa schematic. circuit diagram of the electrical control system associated with one of the. hammering tools. andv feed mechanism for the latter.

Fig. 18. is a fragmentary. section of a nail transfer meansat the; discharge-station of the hammeringtool, thed'jaws of said means being spread apart by the. head of. a .naiLand' being maintained in: spread. position by a. yielda-ble. detent, and Fig; 19 isza: fragmentary section through the.

front wall or muzzle of a modified form of hammering tool.

As shown in Fig. 1, the nailing machine of this invention comprises a nail hopper 20 in the form of a vertical cylinder mounted on a housing or frame 2| containing nail feeding mechanisms, also comprises hammering tools 22 (only one of which is shown) connected with the feeding mechanisms by flexible nail conveying tubes 23 and by flexible electric cables 24, and further comprises a compressed air tank 25 shown connected with a hammering tool 22 by an air hose 26.-

According to the present invention the machine is so organized that a substantial quantity of nails may be placed in the hopper 20 whereupon the nails will be automatically and positively advanced through the nail conveying tubes 23 to the hammering tools 22 when the latter are operated. The tools are so arranged that when applied to work they may be actuated by an operator, and may receive the advanced nails from the conveying tubes and simultaneously drive previously received nails in succession into the work. The entire operation of the machine is automatic and under the control of the workmen handling the hammering tools 22. The operations required of a workman or operator to drive nails into the work are extremely simple and easily performed, so that an absolute minimum amount of skill is required.

When an operator desires to drive nails into the work it is merely necessary for him to grasp one of the hammering tools 22 and apply the muzzle of the tool to the work at the point where a nail is to be driven. Thereupon, by actuating but a single manually operable member, the hammering tool may be made operative and a nail automatically driven into the work to exactly the depth required. When the nail has reached this desired depth, the hammering tool automatically ceases its blows without any attention being required on the part of the operator. The depth to which the nail is driven may be predetermined, so that the nails can be driven flush, or can be countersunk. As soon as the hammering tool ceases to operate, indicating that the nail has been properly driven home, the workman removes the tool from the work and releases the manually operable member, whereupon the tool automatically becomes ready for use again, to drive in another nail.

The hammering tool 22 is extremely compact and of comparatively small size and weight, so that it may be easily manipulated and readily used in places where space is limited, and the flexible connections 23, 24 and 26 extending from the tool 22 may be of substantial length so that the tool may be used over a wide area without necessitating repositioning of the hopper, feed mechanisms and compressed air tank.

Thus, when the machine of this invention is being used in the erection of buildings, the hopper 20 and housing 2| may be located at a central point on the floor of a building if the latter is of small size, and the hammering tools 22 extended to cover most of the locations where hammering is to be done on this floor. Or, the hopper and housing may be located on the floor above that where the hammering tools are being used so that gravity aids the advancing of the nails through the conveying tubes 23.

Referring to Figs. 2 and 3, illustrating the hopper and feed mechanisms, the housing 2| comprises a base '21 having opposite side walls 28 and 29 which support a cover plate 30. As shown in Fig. 3 the cover plate 36 has a large central aperture 3| over which is supported the hopper 20, the latter having cylindrical side walls extending upwardly from a circular base 33.

The base 33 is of the hopper at its underside is provided with a depending boss 34 through which a vertical shaft 35 extends, the boss acting as a bearing and support for the shaft. A paddle 36 is secured to the shaft 35 inside of the hopper to rotate with the said shaft, the paddle comprising a pair of curved oppositely extending blades 3! having along the centers of their rear faces reinforcing webs 38. The outermost and also the bottom edges of the blades 31 are made to extend closely adjacent to the sides and bottom of the hopper 20 so that there is little clearance between the latter and the paddle 36, thereby preventing any nails from becoming wedged in or jammed at these points and stalling the paddle. Nails which are deposited in the hopper 20 may therefore be made to continuously move in circular paths while resting on the hopper bottom by rotating the paddle 36 counterclockwise.

As shown in Fig. 2 the bottom 33 of the hopper is provided with a pair of oppositely disposed, radially extending slots 39 and 45, each slot having an outline substantially similar to that of a nail, but slightly larger in all dimensions.

Considering the slot 40, a depending magazine tube 4|, Figs. 3 and 4, is secured to the underside of the hopper bottom 33 by screws 42 so as to receive and stack in consecutive arrangement nails 43 which fall through the slot.

As shown in Fig. 5 the magazine 4| has a T- shaped bore or interior space which may be occupied by the nails 43 (Fig. 4) in juxtaposed sideby-sicle relationship. The magazine 4| may be formed in any suitable manner. However, I prefer to construct it of a pair of rails 44 and 45 which are joined together in spaced relationship along one edge by a plate 46 having a rectangular groove 41 extending longitudinally in its inner surface. The plate 46 is preferably secured to the rails 44 and 45 by countersunk fillister headscrews 48 as shown.

Thus, if the paddle 36 is continually rotated while the hopper 20 contains nails the latter will be swept over the slots 39 and 4B, and considerin the latter slot, when the nails are properly positioned they will drop through the same and fill the magazine tube 4| in consecutive sideby-side relationship, as shown in Fig. 4.

For the purpose of driving the paddle 36 continuously, the lower end of the shaft 35 is provided with a worm wheel 49 adapted to mesh with a worm 50 carried on a shaft 5| journaled in bearings 52. The shaft 50 has a sprocket 53 driven by a chain 54 which latter is in turn driven by a sprocket 55 of a gear reducer 56 powered from an electric motor 51. Energization of the motor 51 will therefore result in the paddle 36 being continually rotated, and will therefore cause the nails 43 to be fed to the magazine tube 4|.

Adjacent the lower end of the magazine 4| a receiving pipe 58 is mounted, having an inside diameter slightly larger than the heads of the nails 43, Fig. 4. The receiving pipe 58 may be mounted on brackets 59 and 6|! carried by a horizontal shelf 60a as shown in Fig. 2. Intermediate its ends at the point where the magazine 4| is located the pipe 58 is provided with a cut 6| to partially receive one lower corner 62 7 of theraiI- M, see Fig. 4. .Aszshowniin thisrfigure, the corner '62 :is cut off slightly .so that it conforms to the .inside diameter of :the receiving .pipe 5.8. A block :63 is mounted on the shelf 60a of :the housing 2| so thatan upper corner -64 of the block extends along'the outer peripheral surface of the receiving :Dipe 5.8 at "the cut 6-! thereof. The upper surface -65 of the block 63 is made to align with the lower surfaceof the cutBl as shown in Fig. 4., A space :6 6-is provided for between the lower surface of the magazine ,41 and the upper surface 65 of the block, this space being slightly rlarger than the diameter .of the shanks of the nails 43. The upper surface 65 of the block 53 has a short groove 67, indicated by dotted lines, extending :tothe corner 64 to'provide clearance for the heads of the nails Z3, .and thebottom surface of thezmagazine rail 44 has a corresponding-groove BBsimilarly indicated, for the same purpose, Fig. 4.

Also, the wall of the receivingpipe 5,8.adjacent the corner 65 of the block 63 is cut .out as indi cated by dotted lines at '69, so that the cutout is coextensive with the groove 61.

For the purpose of transferring the nails 43 one at a time from the magazine 4| to the receiving tube 58 a transfer slide is provided comprising a plate 7-0 resting on the upper surface 1550f the block 63, the plate having a thickness such that :it may be slidably received between the said upper surface and the lower surface of the magazine 41. A guide for the slide plate '10 is provided in the form of a block H which is secured to the block .63 and extends over the plate 10 as shown.

Reciprocation of the slide plate .10 is accomplished .by a cam 12 carried on a shaft i3, Figs. 2 and .4, the shaft being .journaled in bearings PM mounted on the shelf 60a of the housing. Engaging the cam 72 is a follower 7 inthe form of a block integral with theslide plate Ill. The block 15 is thicker than the slide plate so that ashoulder i5 is provided, .whichis engaged .by one end of a compression spring ll, the spring being enclosed by the guide :block '71 and its other end engaging .an integral shoulder 18 0f the block. The spring TI therefore maintains the follower in engagement'withlthe cam "12, and rotationof the latter will causeireciprocation of the transfer plate l'Jl so :as ;to shift the nails 43 one at a time from the magazine'M into the receiving pipe 58. Preferably the working edge of the transfer plate 10 which en'gagesithe .nails is provided with a concavesurfaceas s'hown,'.and a slot .32, indicated by dotted lines in Fig. :4, is formed in said edge to provide clearance for .the heads of the nails 43.

When the transfer plate '10 is in the :retracted position shown in Fig. 4 it clears the bore of the magazine '4! so that the lowermost mail of the magazine may drop :by gravity from the bore onto'the upper surface 65 of the block 6'3. The succeeding nails 43 will then all descend in the magazine by virtue of their weight, this weight being borne by the lowermost nail resting on the block 63. Since all of the nails are-closely con fined and maintained substantially in alignment side by side there is no possibility of the nail heads overlapping, .or of the nails jamming at any point.

- The cam 12 and shaft '13 .are driven bymeans of a sprocket 80 carried on theshaft, over which a chain 8! runs, the chain also passing over .-a sprocket 82 carried by a countershaft 83, :see Figs. .2 and 3. The countershaft tiiisjournaled in bearingsm secured to :the sidewalliB of the housing, the bearings carrying the shaft in such location-thatthe latter is aligned with the shaft :51 which is being continually driven by the motor 51.

For the "purposeof intermittently operating the countershaft 83 a magnetic clutch 8-5 is provided, connecting the countershaft with the shaft 51., the clutch being made operative by electrical 'energization through wires 86 and 87. Operation of the clutch 85 is accomplished automatinallyas a result of operation of the hammering tool 22 when nails are being driven into the work, as will be more fully explained in detail later. Generally, :for each nail driven by the hammering :tool 22 the clutch 85 is made operative for ailength of time sufficient to cause one cycle of :operation of :the transfer plate '50, said .cycle "comprisingzadvancing movement of the plate to transfer ;a nail '43 :to the receiving pipe .58 and retracting movement .of the .plate back to its starting position,so that a singlenailllS has been removed from below the magazine 4| and placed in the receiving .pipe 58.

Nails from the receiving pipe 58 are transferred to the flexible nailconveying tube 23 for delivery to the hammering tool 22, and for this purpose, as shown in Figs. 2 and 7, the nail conveying tube 23 is'brought into the housing 2i, and its end 23a iscoupled to the end of the pipe 58 within the bracket 60, the end 23a being carried by a roller bearing 6! so as to be easily rotatable. Thus, since the nail conveying tube 23 is aligned with the pipe 58 .nails received by the latter may be moved longitudinally, point foremost into the conveying tube. According to the present invention means are provided :for .forcibly advancing such nails, in successiomthrough the conveying tube 23 to the hammering tool 22 periodically as the tool drives nails into the work and becomes conditioned for receiving nails toreplace those driven.

As shown in Figs. .2 and 3, this positive nail advancing means comprises a plunger SBadapted to extend through the boreof the pipe 58 so that nails disposed in the latter from the magazine 4i maybe driven past the point of transfer. The outer-end of the plunger 88 has a head 89 provided with a driving 'pin 98 which latter is engaged by the fork SI of a lever 92 pivotally mounted on a block 93 secured to the shelf 60a. The lever -.92 has a follower 'pin .94 extending into the groove of a cylindrical cam 95 which is mounted on the shaft 13 .to rotate therewith.

Thus, at :the time that the transfer plate 70 is advancing .to transfer a nail into 'the receiving pipe 58 the plunger 28B is being withdrawn from the pipe ahead of the plate by the lever 92 and cam 95. After transfer of .a nail, and when the plate it is being retracted the plunger 88 is advanced within thepipe 58 causing the transferred nail to be advanced .and shifted point firstpast the :transfer opening in the pipe, thereby making way for a succeeding nail.

Repeated periodic operation .of this transfer and feed mechanism as controlled by the magnetic clutch will therefore cause the nails 63 in the magazine .4! to be disposed in succession, points foremostwithin-thenail conveying tube 23 so as to completely fill the latter andextend to the hammering tool '22.

'Toifacilitatethe feeding of the nails 43 through the flexible conveying tube 23, according to this invention, means are provided for :periodicalli rotating the tube in step with the operation of the transfer and feeding mechanism controlled by the clutch 85. For this purpose the end 23a of the conveying tube, which is carried by the bracket 60 so as to be rotatable therein, has a sprocket 95 mounted on it, the sprocket being driven by a chain 96 which is in turn driven from a sprocket 91 carried by the shaft I3. Thus the nail conveying tube 23 is made to rotate intermittently, its rotation occurring during the periods that the magnetic clutch 85 is driving the transfer and feeding mechanism for the nails, and by this organization there is minimized the likelihood of the points or heads of the nails becoming wedged or jammed at anyplace within the conveying tube 23.

Referring again to Figs. 1 and 2, the hammering tool 22 derives its power through the air hose 26 from the compressed air tank 25, which latter is supplied by an air compressor 98 driven through a coupling 99 from the gear reduction unit 56.

Considering now the hammering tool 22, the latter is shown in axial section in Fig. 8. The tool has a casing comprising a handle portion I integral with an elongate base portion IOI on which latter there is mounted a housing I02 for the driving mechanism of the hammer, the said mechanism including a cylinder I03. The housing I02 at its foremost end has an upward extension I04, and is provided with flanges I at said end to which a nosepiece I06 is secured by screws I01. In its front face I08 the nosepiece I06 has a muzzle I09 in which there is an aperture H0.

The upwardly extending portion I04 of the housing I02 is bored to receive a press-fitted sleeve III which extends rearwardly therefrom. The rear end II2 of the sleeve III receives and has rigidly secured to it a flexible conduit 3 which incloses the nail conveying tube 23 and protects the latter against injury, as well as permitting rotation of the tube without interference.

For the purpose of rotatably mounting the conveying tube 23 within the sleeve I I2 for easy turning, a pair of ball bearings I I4 and H5 is provided separated by a spacer sleeve I I6. The nail conveying tube 23 extends through and is carried by the ball bearings I I4 and I I5, and is therefore free to rotate easily when the tube is being driven during advancing movement of the nails 43. A collar III is secured to the tube 23 adjacent the bearing H5 to prevent undue axial movement of the tube.

According to the present invention a novel nail transfer and supporting means is provided within the nose portion I06 of the tool casing whereby nails 43 may be received from the conveying tube 23 and may be consecutively automatically positioned preparatory to being driven out through the muzzle I09 into the work. This means is in the form of a drum or rotary member I I8 having a core portion II9 whose ends I20 and I2I are of reduced diameter and are carried in bushings I22 and I23 located one in the front wall of the nosepiece I06 and the other in a strut I23a across the rear of the nosepiece, Figs. 8 and 10. The core H9 of the rotary transfer member is thus rota ably mounted to turn within the nose portion of the tool casing. A plurality of nail receiving and supporting means I24 are carried by the core portion II9 of the transfer member II8, said means being located in squirrel cage arrangement about the core portion and each comprising a-pair :of laws I25 and "I26 mounted on 'shafts'I2T which latter at their ends are carried by circular flanges I28 and I29 0f the core portion H9. "The jaws I25 and I26 have semicylindrical, longitudinally extending grooves I30 and I3I respectively which cooperate with each other to provide a cylindrical cavity adapted to accommodate the shank of a nail 43, as shown in Figs. 8 and 11.

Referring to Fig. 8, the grooves I30 and I3I have tapered and enlarged portions I32 and I33 respectively which cooperate to form an enlarged mouth or entrance for the nails, and when the 1 heads of the latter are driven forward from the mouths into the grooves I30 and I3I, causing the jaws I25 and I26 to spread apart, the nailheads will engage a ridge or rib I33a in the nose portion I06 of the casing, thereby maintaining the nail heads centralized during the driving operations. The circular flange I29 of the core H9 is of sufficient diameter to extend past the rearend surfaces of the jaws I25 and I26, and circularly disposed apertures I34 are provided in said flange to align with the enlarged mouths-of the jaws. As shown in Fig. 8, the apertures I34 are slightly larger in diameter than the heads of the nails 43 so that the nail heads may be driven through the apertures at the time that the nails are being discharged from the muzzle I 09. Prior to the passage of the nail heads through th apertures I34, and when the nails 43 are being supported by the jaws I25 and I26, the shanks of the nails 43 will be centralized in the apertures I34, so that the nail heads are properly centralized and will not meet with obstruction when being driven out of the muzzle I09. The jaws I25 and I26 are yield-ably held together by coil springs I 35 carried on the shafts I21 and engaging the jaws and the core portion I I9 of the rotary member.

As seen in Fig. 8, the jaws I25 and I26 are so carried by the core portion I I9 of the rotary member IIB that when the latter is rotated, the nail receiving cavities formed by the jaws will become successively aligned with the nail conveying tube 23. Thus, nails 43 may be transferred from the tube 23 to the nail transfer and supporting means I24 in succession, and the nails will be frictionally held by said means until driven therefrom by force.

The station occupied by a nail transferring and supporting means I24 when aligned with the nail conveying tube 23 I term a loading station. The point diametrically opposite this loading station-I term a discharge station, this being the point where a nail transfer means I24 is aligned with the aperture I I 0 of the muzzle I09.

For the purpose of insuring proper alignment of the nail transfer means I24 at the loading and discharge stations a detent is provided in the form of a plunger I36 charged by a spring I31 Thus, when the rotary member I I8 is turned, the

detent means comprising the plunger I36 and the flange I29 will tend to position the nail transfer means I24 consecutively in proper alignment at the loading and discharge stations.

According to this invention a novel hammer or driving means is provided for driving a nail sup ported at the discharge station, point foremost, through the nozzle I09 and into a workpiece with sufiicient force to completely sink the nail up to its head. This means comprises a plung'er'or hammer member I48 connected with. a piston I41 whichzlatterlsreciproca-ble-in. the cylinder I08:

Theforemosti endof' the cylinder 103*- is. provided witha closureor head 1112- centrally apertured'to slidablyreceive. the plunger I40, thehea-d having: a packing I43. held in .place by a ring. I44 threaded into the head.

' Thepiston MI is madertorapidly automatically reciprocateunder. pressure .from compressed-air fedthrough the. air hose 2'6. leading-afromv the tank ply duct: I49 which'isconnected through a fitting I58 with-the air hose-26. The. air'is diverted according to-the position of the valve I 48 intoreither of. two ducts I5I and I52 extending upward through the handle portion: I and supplying the cylinderI03.

1 Asclearly shownzin'Fig. 8,.the valve. I48 is carri'ed'in-a: stepped bore in the. handle I00, the bore having aportionof smalldiameter I53 anda portion-oflarge diameter I-54gthe latter beingclosed byathreadedplug I55. The valve I48 comprises a-hollow-body- I55 in which a compression spring I51 is carried, the spring engaging the plug I55 and yieldably holding the valve in extended position as shown. The body- I56 of the valve has three spaced circular flanges I58,-. I59 and I60 which'fit-closely to-the insidesurface. of the enlarged' bore portion I54. A neck II of smaller diameter than the: bore. portion. I58 extends through the latter and terminates in a head I82 which is-nor-mallylocatedoutside of the bore portion I'53but'is-oi a size to: closely slidably fit said portion when the trigger is depressed: and the valve moved tO aretracted position With-the. parts as shown in.Flg. 8 air. from the duct I49'isconducted through the duct I5 Iwhich,

V asshowninFig. 13,- connects-with aduct I63 in the underside.- of theshousing I02- ofthetool casing. The'du'ct. I63 extends forwardly and connects with a port I85 opening into the forward end of'thecylinder: I 03 closely adjacent-thehead I 42 thereof. This: causes an". air pressure" in the forward chamber ofthe cylinderand onthe for- Wa-rd'iface offthe piston I41. maintaining thelatter in its retracted'or starting position-shown. A second port I55 opens into the-cylinder I03 closely adjacent the port I64 but slightly rearward thereof.- Thisport I65 connectswith-wa-duet I66 theunderside of: the housing I02 of the. casing, Fig.- 13-. Referring to Fig. 8, the ductv 186 comnects with a vertical'du'ct I 61 inthe handle por-'- tion I00-ofthecasing, thelatter duct opening into the enlarged'valve bore I54 between the flanges I59-and I60-ofthevalve I48, and said-flanges sealing off the duct when'the valve. is inextendedzposition. Therefore. even though: there. is. a second port I65in the forward chamber of the cylinder I83,.no.-air can escapethrough this port-when the parts are inthe positions show-nin Fig. 8; andthe cylinder I II wilt-be maintained in. retracted position.

For the purposeofautomatically reciprocating the piston I- t-I when the trigger I'45- depressed the valvev l ialretracted so asto causecompressedlairi to'flow'into the duct I52, a reversing valve in the form: of a piston I68 is provided in therea-rwa-rd. portion; ofthe cylinder I03, said valve being, adapted. for. automatic operation.- in response tothe. movements of, the-v piston I41. The-reversing: valve I68 has abody. portion I89 ofsmaller diameter thanthe. inside ofv the. cylin-- der I03. Attheendsof the body portion I69-are flanges I10 and HI respectively which closely slidably fit. and seal. against the; inner walls.- of the cylinder. I03, and intermediate the flanges I10. and. I.1I. thereisprovided a third flange I12. also sealing, againstthe cylinder walls.

Normally, the valve. I68 is in arearwardrposition asshown in. Fig. 8, being; held therein by a plunger extension. I13-carriedlby the. piston I 1l which extension .engagesthe forwardend. face. of the valve I68. The air duct. I52. whichreceives air when the valve I48 is retracted connects with a duct. I14, Figs. 8 and 13,-)formedintheundersurfaceofthe housing- I02 ofthe toolcasing. The dust I14 connects. with a port. I15. opening, into the cylinder. I03betweenthe flanges. I11!v and. H2. of the reversingvalve I.6.8.. Communicatingwith the space. betweenthese flanges I10.. and- I12 of the. valve. isa. port. I16 which. connects with. a duct. I11, Fig. 13,. the latter connecting with. a port- I18 openinginto the cylinder I103. just. be-

yond. the rear face of the piston I.4I.. This causes.

an air pressure against the. face. of the. piston and drives the latter forwardly in. the cylinder. I03;

A. nail carried in the nailtransfer means. I24. atthe discharge stationv alignedwith the plunger I40 will be struck a blow on. the head by the plunger, thereby driving the nail, point out partially through the muzzle I09 and into the. work. During the. forward movement of. the piston. I4I, the chamber in the cylinder ahead ofthe. pistonvvill be vented through the port. I as follows; This port connects with the ducts I65 and 181', the duct I61 communicatingwith a duct. I19 since both of these latter are located between the flanges I59 and I58 of the depressed valve. I48. The duct I19 connects with. a duct I88, in turn connecting with a port I8.I opening into the cyl inder' between. the flanges. I10. and. I12 of the reversingvalve: I58. A vent'port I82 is provided in the cylinder wall between the flanges I1 I. and

I12 of the valve I68 so. that the port' I8I thus communicates withthe port I82 and is therefore vented to. the. atmosphere As. a result the air in the. forward chamber of the cylinder I03 ahead of the piston IAI may escape to the atmosphere. as the piston is forced forwardly.

I The piston I4I will come to rest at some point wherein its rear face is beyond a port I83 opening, into the cylinder I02. When the piston MI comes to rest, the air'which has been driving it will be forced through the port I83 and through a duct I84, Fig. 13', in the undersurface of the housing I02of'the casing; The duet IMconnects with aport I85" opening into a bore I86 in the rear end ofthe housing I02. This bore is closed by a threaded plug I81, and contains a piston I88having a plungeror pin' I89 extending through a transversewall. F90 to the rearface of the valve I68; A. compression spring I91 is; carried about the pin; I89; engaging one end-face of the piston I88.- and' the-transverse wall. I90 soas. to yieldably holdthepiston in-a retracted. position as shown. The piston. is. prevented from abutting the plug I81 by means of a central boss I92 whichserves to space ittherefrom. and prevent. sea-ling off of. theport [85. The pin I89 passes through packing I93 held in thetransversewall I90;by a threaded ring" I94. I

When air is. forced into the: port I85 itzmoves 13 the piston I88 and pin I89 forwardly against the ,pressure of the spring I9I, and in so doing moves the reversing valve I68 forwardly to the extent that the flange I12 thereof passes the port I15 and comes to rest immediately ahead of the latter. The forward movement of the valve I68 is limited by a pin I95 which extends into the cylinder between the flanges I12 and HI of the valve for engagement with the latter flange.

When the reversing valve I68 has been moved forwardly the port I15 which is being supplied with compressed air is made to communicate with the port IBI, Figs. 8 and 13, which latter port is connected with the duct I88, the duct in turn connecting with the duct I19, Fig. 8. Due to the retracted position of the valve I48 the duct I19 is still in communication with the duct I61, which latter is connected with the duct I66 and port I65. Thus, compressed air is brought in again into the forward chamber of the cylinder I83, causing the piston I4I to be rapidly moved rearward to its initial starting position. When the air is entering the port I65 it cannot escape through the port I64 since the ducts I63 and II connected with the latter are sealed off due to the fact that the duct I5I opens up into the space between the flanges I58 and I59 of the retracted valve I48, and since said flanges prevent the escape of air.

During the time that the reversing valve I68 is in its forward or shifted position, and when the piston MI is being forced rearwardly the port I18 in the cylinder is connected so as to vent into the atmosphere and thereby permit the air to the rear of the piston to be discharged. This venting is accomplished by means of a vent port I99 in the wall of the cylinder I83. When the reversing valve I68 is in the forward position the vent port I99 communicates with the port I16, since both of these lie between the flanges I 18 and I12. Since the port I16 is connected by the duct I11 with the port I18, the latter is therefore vented to the atmosphere.

At the time that the reversing valve I68 is in its forward position and when the piston I4! is being driven rearward the vent I82 is closed off by the flange III of the reversingvalve so that air from the port I15 cannot escape through the vent, but must pass through the port I8I, the ducts I88 and I19, thence through the ducts I61, I66 and the port I65 to drive the piston I4I back. Similarly, when the reversing valve I68 is in its rearward or starting position the vent port I99 is closed off by the flange I18 of the reversing valve, so that air issuing from the port I15 into the cylinder cannot escape through the vent but must pass through the port I16, the duct I11 and through the port I18 to drive the piston I4I forward.

At the time that the piston I4! is in any of the successive forward positions that it assumes as it drives a nail 43 deeper and deeper into the work, and also when the piston is being forced rearward, the reversing valve actuating piston 588 will be in retracted position as shown, having been moved to this position by the coil spring I9I. This is because, since the hammering piston I4I has come to rest in forward position and has caused the valve operating piston I 88 to advance and shift the reversing valve I68 forward. the air driving the piston I88 is thereby vented. The venting of this air is accomplished as follows: With piston MI and the reversing valve I66 in forward positions, the ports I83 and I18 will, of course, be in communicationv with each other, and the port I18 will be venting through the duct I11 and ports I16 and I99 to the atmosphere. Thus, the air occupying the space between the piston I88 and the plug I81 may pass out into the atmosphere, since the port I 85 connects through the duct I84 to the port I83. Therefore, the spring I9I will return the piston I88 to its initial or starting position, and this will enable the hammering piston I4I when it returns to retracted position to drive the reverse valve I68 ahead of it so that the latter is also returned to starting position.

By the provision of a duct zoo, Figs. 8 and 12,

extending between the opposite end faces of the reversing valve I68 the latter may be shifted either forward or rearward by the pin I89 and. plunger I13 respectively without being retarded due to trapped air on either side of the valve. To yieldably hold the valve I68 in either forward or rearward position, a cletent is provided comprising a ball HM and spring I151) carried in a recess in the housing I82, see Fig. 12, the recess being capped by a closure I120. The ball I12a is adapted to engage the flange I12 of the valve I68, and. by advancing slightly past either the forward or rearward edge of the flange, functions to prevent inadvertent movement of the valve. I

When the trigger I45.is released, it is returned to the extended position shown in Fig. 8 by a coil compression spring 28! engaging the rear surface of the trigger and the opposite interior surface of the handle portion I88 within the recess I 41. Upon the trigger I45 being released the trigger operated valve I48 will be returned to its extended position shown by the coil spring At the time that a nail 43 is driven partially through the nail transfer and supporting means I24 at the discharge station, the head of the nail will cause the jaws I25 and I26 of the said means to spread apart considerably, as shown in Fig. 18. When the nail head has just left the nail transfer means I24, but is still in the aperture I I8 of the muzzle I89, the jaws I25 and I26 will be held apart by a detent plunger 282 having a yoke portion 283 and upstanding fingers 284. The plunger 282 is continually urged upwardly by a compression spring 285, the latter and the plunger being located in a bushing 286 carried in an internal recess 281 in the nose portion I86 of the tool casing.

' Referring to Figs. 8 and 10 the plunger 282 has a rounded head 288 adapted to engage the periphery of the flange I29 of the rotary transfer member H8, and adapted to enter the notches I39 of said flange so asto function as a detent in con unction with the detent plunger I36 at the 'top of the nose portion I 86' of the casing. Referring to Fig. 1l, when the rotatable transfer member H8 is turned from the position shown, the plunger 282 will be depressed by engagement of the head 288 thereof with the periphery of the flange I29, and the fingers 284 of the plunger will be retracted so that they do not engage or. interfere with the jaws I25 and I26 during the latters travel to the next, succeeding position. However, as shown in Fig. 18, after the jaws I25 and I26 have been spread apart by the head of a nail being driven into the work, the fingers 284 of the detent will engage the mating surfaces of the jaws and prevent the latter from moving together again until the rotary transfer member II8 has been rotated. Thus, the hammering plunger I48, when driving I I a: nail the last. fraction of an inch through. the aperture I ID of the muzzle Hi9, will not strike the jaws I and H26 nor be interferred with in. any way by the latter.

It thus be seen that, referring to Fig. 8, when the trigger M5 is depressed to move the valve I 48 inward to retracted position, the air pressure in the air hose 26 will cause a rapid automatic reciprocation of the piston MI and hammering plunger I 40; Each succeeding reciprocation of the piston and plunger will drive a nail 43 at the discharge stationdeeper into the work, and therefore the forward travel of the prime. and plunger will become increasingly greater as the reciprocation continues.

Means are provided, according to the present invention, forautomatically holding or stalling the. piston Mi and the plunger I40 when a predetermined advanced position of the same hasbeen reached, indicating that the driven nail has reached the desired depth in the work. In accomplishing this, the port IE5 is utilized. When the driven nail has reached the desired depth, the forward position of the piston Mi will be such that. the port !65 will just be covered and sealed off by the front edge portion of the piston. As soon as this occurs, of course, the driving air will have been prevented from entering the forward chamber of the cylinder ahead of the piston 14 and therefore the latter will not be returned to its: starting position but will remain stalled in fully extended position. Thus, the reciprocation of the piston hi! and plunger I'M will be automatically halted even though the trigger M5 is. held in, and the valve M8 is in its inward or retracted position. This signifies to an operator that the nail has been driven in by the machine to the extent desired. Upon release of the trigger M5, the trigger'operated valve I43 will'be moved to its extended position, and air from the duct his will again pass through the ducts l5! and F68, and through the port Hid which, not being covered! and. sealed off by the piston MI, will permit the air to drive the piston rearward to its starting position.

According to the present invention means are provided, responsive to the operation of the trigger M5 for automatically rotatably advancing the rotary transfer member i 18 upon completion of the driving in of a nail, and for automatically feeding another nail into an empty'nail transfer means 52 shifted to the loading station, to make up for the driven nail so that the successionof nails fed to the discharge station will not be interrupted.

The, automatic rotation of the rotary transfer means i if: is preferably accomplished during the V releasing movementof the trigger I45, and after the trigger responsive valve I48 has been returned to its extended position, inactivating and, returning the hammering plunger: Hill and piston Ml toretracted, starting position.

To accomplish. this, the top surface of the trigger m5 is provided" with a wide notch 2B9, Figs. and 14, into which there extends a pin 2E0 carried: by a sliding link 2 carried f'orwardlyin a deep longitudinal groove-2 l 2- in theundersurface of. the housing N12 of the tool casing. The front end 2 l3 of the link 2-H is apertured and pin connected to a bell crank-.2 l4 located in a recess 2 Hand pivoting on a pin 216 secured to onewall of the recess.

ries a pawl2 l 8, Fig. 10. Aratchet 2 i9 is mounted onand is keyed, to the reduced pivot portion, l2!

. 16 of the core- I lie of the rotary-transfer member H58 and is located forv engagement with the pawl 21-8, to be driven by the latter. A flat spring 226 is secured to the link 2 H for yieldably maintaining the pawl 2 l8 in engagement with the ratchet 219. Also, a wire spring 22 carried-on a pin 222 is anchored at one end'to the bell crank 2M and at the other end to the link 2!? to yieldably hold the latter forwardly in a vertical transverse plane. When the trigger M5 is being depressed, during the final part of its movement it will engage the pin 2!!! and pull rearwardly the link 2", thus operating the bell crank 2M and lowering the pawl 2l8, see Fig. 10, until the latter engages thev next or succeeding tooth of the ratchet 2P9. This does not disturb the rotative position of the rotary transfer member H3,"however, and since the trigger is now depressed the plunger I and piston i l! will be operative to hammer in a nail.

However, upon completion of the nail driving, when the trigger M5 is released, it will move outwardly an extent until the valve M8 is returned to extended position, the valve causing withdrawal of the piston MI and the plunger MB- to their retracted, starting positions. As the trigger I moves further to its extended position under the urging of the spring 20], the pin 29! will be engaged by the trigger and the latter will drive the link 2 forward, raising the pawl N8 and rotating the rotarytransfer member 5 l8 through one-sixth of a revolution, thereby aligning the next set of nail transfer means l24' respectively with the loading anddischarge stations. Thus,

a nail 43 carried by the nail transfer means 124 which has been newly brought into alignment with the hammering plunger ill will be in readiness for driving. Also, an empty transfer means l24 will be aligned with the nail conveying tube 23 at the loading station in readiness for receiv ing another nail. Feeding of the nails 63 from the nail conveying tube 23 into the empty nail The bell crank 2| 4, is in turn pivotally connected to alink 217; which. pivotally'ca'rtransfer means E24 is also accomplished auto matically, according to the present invention, during the actuation of the trigger M5. Preferably this is accomplished during the time that the trigger M5 is being depressed, and for this purpose an electrical switch 223 is provided, mounted in the handle portion I00 of the tool casing below the trigger I45, said switch having a plunger 224 adapted to be engaged and driven bya shoulder 2 25 of the trigger. 1

' Referring to Fig. 17, the switch 223 is of the single pole double throw'type, and has three wires 226, 221, and 228 extending from. it comprising a flexible cable 229 which is led into the housing 2.!

of the feed mechanism.

The switch 223, Fig. 17, has a blade 23o operable by the plunger 224 and connected with the wire 2'26, and has contacts 23! and 232 for cooperation with the blade 239. Normally, when. the trigger l 45 is in its released position, the switch blade 2% is touching the switch contact 232. When the. trigger M5 is depressed, the switch blade 230 leaves the contact 232 and engages the contact 23 l.

A novel circuit control is provided in connection with the switch 223, and with the magnetic clutch 85, whereby the feedingmechanism which transa fers the nails 43 from the magazine 4! into the receiving pipe 58, and which advances the nails in said pipe and through the nail conveying tube 23, ismade to operate through but a single cycle so as to transfer a single nail and advance the nails in the tube by one for each operation of the trigger I45 and the hammering tool 22. This cycle is carried out in response to depressing the trig- 'ger I45, and once initiated will proceed to its completion even though the trigger is inadvertently released before the hammering has been completed. Also, after the cycle has proceeded to completion, it cannot be repeated while the trigger I45 remains in depressed position regardless of how long the latter is held in said position. Thus, each time that a nail held in the tool 22 is driven into the work by the hammer, one nail only will be delivered from the nail conveying tube 23 to replenish the nails in the tool, and after such delivery the feeding mechanism will automatically become inoperative without requiring any attention on the part of an operator.

Referring to Fig. 17, the control which accomplishes this automatic feeding comprisesa relay 233 having a pair of armatures 234 and 235 adapted to respectively engage contacts 236 and 23?. When the relay 233 is deenergized, the armatures are normally separated from the contacts, providing an open circuit condition. Associated with the shaft I3 and cam 12 of the nail transfer mechanism for the magazine 4|, there is provided a pair of rotary cams 238 and 239, see Figs. 4 and 17. These cams are carried on the shaft 13 to rotate therewith, being located adjacent the sprocket 91. The cam 239 has a wide notch 249 in a circular periphery 24I, for engagement with a switch actuating arm 242 operating a microswitch 243, see Fig. 16. The cam 238 has a narrow notch 244 in a circular periphery 245, for engagement with a switch actuating arm 243 operating a microswitch 241.

Referring to Fig. 16, the microswitch 243 is carried on a vertical supporting plate 243 which is mounted on the base 2'! of the feed mechanism housing 2|, and the microswitch 241 is located directly opposite the microswitch 243, on the other side of the vertically supported plate 248, Fig. 3.

As shown in Figs. 4, 16 and 17, a latch 249 is provided, mounted on the vertical plate 248 and adapted to maintain the switch operating arm 242 in depressed. position after it has been moved to said position by rotation of the cam 239. Associated with the latch 249 is a magnet 255, which, when energized, operates the latch to release the switch operating arm so that the latter may be moved to extended position wherein it occupies the notch 240 of the cam.

Referring to Fig. 17, the circuit connections for the switch 223 of the automatic feed control are as follows: The wire 225 comprises one side of a supply line. The other side of the supply line comprises a wire 25! which connects with one end of the coil 252 of the relay 233. The other end of the relay coil 252 is connected by a wire 253 to one contact 254 of the microswitch 241, and this is connected by a jumper 255 to one contact 255 of the microswitch 243.

The wire 22'! leading from the trigger operated switch 223 connects with one end of the magnet coil 259, the other end of which is connected by a wire 25'! to the line wire 25 I. The wire 228 leading from the switch 223 connects with the other contact of the microswitch 243, represented diagrammatically by the switch operating arm 242 in Fig. 17. The remaining contact of the microswitch 241, represented diagrammatically by the switch operating arm 246 in Fig. 1'7 is connected by a wire 258 to the relay armature 234, and the relay armature 235 is connected by a wire 259 to the magnetic clutch 85 whose other connection is thru a wire 26!) to the line 25I. The relay contacts 233 and 231 are connected together by a 18 jumper 26I which latter is connected by a wire 262 to the line wire 226.

Fig. 17 shows the position of the various parts of the control when the trigger I45 is in released position, the hammering tool 22 being in readiness for use. The magnet 250 is continually nergized, maintaining the latch 249 in releasing position. The microswitch 243 is normally closed, and the microswitch 241 normally open, and the relay contacts normally open. When the trigger I45 is depressed, the circuit is broken thru the magnet 259, thereby releasing the latch 249. Also, a connection is made between the arm 239 of the trigger operated switch 223 and the contact 23I thereof, and this energizes the relay coil 252. Immediately, the relay contacts are closed, thereby energizing the magnetic clutch 85, whose energization causes the shaft 13 to be driven, operating the transfer mechanism between the magazine 4| and the nail-receiving pip 58, and also operating the feeding mechanism comprising the plunger 38.

Rotation of the shaft 13, which is in a clockwise direction, causes the cams 238 and 239 to rotate clockwise. At the initiation of movement of the cams, the microswitch 24'! will be closed, thereby completing a holding circuit for the relay coil 252 thru the relay contacts 235 and 234. Thus, if the trigger I45 should be inadvertently released, it could not halt th operation of the nail transfer and feeding mechanism since the energization of the relay 252 will be maintained thru the holding circuit. As the rotation of the cams 238 and 239 progresses, the microswitch 243 will be opened, thereby rendering inoperative the connection provided between th arm 233 and contact 23I of the trigger controlled switch 223.

The cams 238 and 239 will continue to rotate thru a single revolution representing the cycle of operation of the nail transfer and feeding means, during which cycle one nail will be transferred from the magazine M to the receiving pipe 58, and the nails in the receiving pipe 58 and the nail conveying tube 23 will be advanced by one. This advance causes the foremost nail in the conveying tube 23 to be transferred into the empty nail conveying means I24 waiting at the loading station. Upon completion of the one revolution of the cams 238 and 239, the microswitch 241 will be opened by the arm 245 entering thenotch 244. This will deenergize the relay coil 252, since it opens the holding circuit for the relay. However, during the rotation of the cam, the switch operating arm 242 has been caught by the latch 249 so that it is held in de-- pressed or open-circuit position. Upon completion of the revolution of the cams 238 and 239, the switch operating arm 242 will not again drop into its notch 249 since it is prevented from doing so by the latch 249. Thus, although the trigger I45 is held depressed, the relay cannot be again made operative to cause the cycle of the transfer and feeding mechanism to be repeated, since energization of the relay after its holding circuit has been broken must be effected through the microswitch 243.

The time of the cycle of operation of the nail transfer and feeding mechanism as brought about by the control circuit shown in Fig. 17 is preferably shorter than the time required for the hammering tool to fully drive a nail into the work, so that when the tool automatically stops after the nail has been driven home the feeding 7.5 of a new nail to the tool 22 has already been com- '19 pleted. However, it is not necessary for this cycle to be shorter than the time required for a nail to be driven home, since the cycle carries on to completion even though the trigger M is released.

After a nail 43 has been driven by the hammering tool- 22 and the feeding of a replacement nail completed, and when the trigger M5 is being released, the switch arm 230 of the trigger controlling switch 223 will be disengaged from the contact 23! and will again engage the contact 232, reenergizing the magnet 25% and pulling the latch 249 to releasing position, whereupon the switch operating arm 242 will be released and may again enter its associated notch 260 in the cam 239. Thereupon the control system is returned to its initial position, in readiness for another cycle of operations at the time that the trigger M5 is again depressed to drive in another nail.

According to the present invention a safety device is provided in connection with thehammei ing tool 22 whereby inadvertent operation of the latter while the muzzle thereof is not being held against a workpiece, is prevented. Thus,

there is minimized the likelihood of a nail being forcibly and with great speed projected from the muzzle of the tool while it is bein held in the hands of an operator, either during moving of thetool to a new spot for the driving inof a nail, or while it is being otherwise handled. Such a nail inadvertently ejected from the muzzle would become a missile which might cause serious injury to a fellow workman or to other persons.

In accomplishing this, referring to Figs. 8, 9, 13 and 14, a pressure operable ring 263 is provided, mounted on a plunger 264 so as to be carried in front of the muzzle I09 in alignment therewith and spaced therefrom. The plunger 264 extends into a bore 255 in the nose portion 36 of the tool casing, and has a limited axial movement therein as provided by an elongateslot 266 in the plunger receiving a stop pin 26! carried by the casing. The plunger 264 is yieldably held in extended position by a compression'spring 268 located between the inner end of the plunger and a shoulder 269 of the casing. A fiat link 2') connected with the plunger 264 extends rearwardly thereof through the spring 268 and through a deep longitudinal groove 21! in the undersurface of the housing I02 of the tool casing, the rear end of the link terminating in a tapered portion2i2. For cooperation with the tapered end 272 of the link 212, Fig. 14, a pin 2'13 is provided carried on a lever 214 pivotally mounted on a pivot pin 2'55 carried by the housing I02. When the plunger 264 and link 21!] are in extended position as shown, the pin 273 is held in engagement with the tapered end 212 of the ring by a plunger 2H3 charged by a compression spring 217, both plunger and spring being carried in a recess 278 in the base portion Iii! of the tool casing. The other end of the lever 274 has a ShOUIdEYZTQ forming a latch adapted to engage the notch 299 of the trigger i 45. Normally, with the partsin the positions shown in Fig. 19, which positions are occupied when the tool 22 is not being held against a workpiece, the lever 214 locks the trigger M5 so that the latter may not be depressed to cause operation of the hammer. However, when the hammering tool 22 is pressed against a workpiece, the ring 263 is moved backward against the muzzle its, causing the plunger 264 and the link 21!] to move inward or rearward, thereby partially pipe 28!.

rotating the lever 2M counterclockwise and releasing'the trigger I 35. The hammering tool 22 may thus be operated without danger of a nail being projected into space from the muzzle, to possibly cause personal injury. After the hammering has been completed and the trigger M5 released, and the tool 22 is removed from the work, the safety ring 263 and the plunger 26% will again be extended by the compression spring 288, thereby'locking the trigger M5 against inadvertent movement.

In the broader aspects of the invention the hammering tool '22 may be supplied with nails by means other than the nail conveying tube 23. For example, other well-known types of magazine feeds may be employed to deliver nails to the rotary transfer member H8.

According to this invention, the nailing machine may have a plurality of nail feeding and conveying means, so that a plurality of nailing tools 22 may be employed, to be supplied from the single hopper 20. Accordingly, as shown in Figs. 2 and 3, the nailslot 39 in the bottom of the hopper connects with a second nail magazine 288, see Fig. 6, which latter is adapted to stack nails for transference to a nail receiving A nail transfer member 232 is provided, having a U shape, said member being adapted to slide between a guide provided by a block 283 mounted on the shelf 284 and by a block 285 and rails 286 and 213i of the magazine 28%. The transfer member is integral with a cam follower 288 slidable on the block 283 under a guide 283a, the follower being charged by a spring 2832) to maintain it in engagement with a earn 289. The cam 289 is carried on a shaft 292 journaled in bearings 2% which are mounted on the shelf 2%. Motive power for the shaft 2% is provided through a sprocket 292, chain 293, and sprocket 29 1 which latter is carried on a countershaft295 journaled in bearings 29% mounted on the side wall 28 of the feed mechanism housing. A magnetic clutch 29! is provided for coupling the countershaft 295 with the shaft 55 which latter is continually rotating.

For feeding nails from the receiving pipe 22! to .the other flexible nail conveying tube 23, a plunger 29%] is provided, slidable in the pipe and operated by a slotted lever 299 engaging a driving pin-30c carried by the head 3231 of the plunger. The lever 2Q9is pivotally mounted on a bracket 382 secured to the side wall 29 of the housing, and is operated by means of a pin or follower 3B3 engaging a cylindrical Cam 3% carried by and rotatable with the shaft 296.

The receiving pipe 28l and the nail conveying tube 23 are coupled at their ends in a bracket 305, and the tube is adapted to be driven or turned through a sprocket 386 andchain till, the latter running over a sprocket 328 carried by the shaft 292. The operation of this transfer and feed mechanism is similar to that already described in connection with the nail magazine ii.

A control mechanism is associated with the feed mechanism, substantially similar to that already described and shown in Figl'l, said control including cams 329 and 3M) carried by the shaft 2%,and including microswitches 3H and 312, Fig. 3, mounted on the vertical supporting plate 248 for operation by the cams 369 and 35m. The

microswitch 3H2 has associated therewith a latch 313 and magnetic operator 314 therefore, similar to the latch 2'49 and magnet 2% already described.

The microswitches 3H and M2 are connected in circuit with a suitable relay and with the magnetic clutch 291 to control the operation of the latter in response to movement of the trigger of a second hammering tool 22, so that the transfer and feed mechanism operates through one complete cycle for each actuation of the trigger, as already described.

The hammering tools 22 are compact, light and easily carried, and may be manipulated, applied and operated by one hand of a Workman. Thus, in the erection of a structure, the workman may hold the member to be nailed with one hand, and apply the hammering tool 22 to the member with the other hand, so as to conveniently and quickly drive a nail into the member to secure it in place. The workman is relieved from continually having to reach for nails, as Was heretofore necessary; nor do there occur the time-consuming incidents such as retrieving dropped nails, straightening bent nails, etc. The nails may be driven in by the tools 22 at an angle, or straight, and in quick succession, all to the proper depth.

It will thus be seen that by the present invention there is provided a highly efficient, automatic nailing machine wherein a large quantity of nails may be deposited in a hopper and automatically fed to a plurality of hammerin tools as these latter require replacements for the nails driven into the work. Each hammering tool is operated solely by a single member or trigger in such a manner that no skill is required on the part of an operator. The trigger not only controls the startin of the hammering means, but also automatically controls the feeding of nails to the tool, and automatically controls the presentin of nails in front of the hammers to be driven thereby into the work.

The hammering tools are compact and small in size, and readily maneuvered so that they may be used in constricted spaces. The flexible connections to the hammering tools permit them to be held at various angles without difficulty, and by virtue of the substantial length of these connections permit the tools to be used over a considerable area without necessitating shifting of the hopper and feed mechanisms. Also, the tools are safe during use and during handling due to the provision of the means for automatically preventing inadvertent operation of the hammer when the tool is not being held against the work.

The nail feeding and conveying mechanism associated with each of the hammering tools is automatically controlled in a manner that it completes a single cycle of operation each time the trigger of the hammering tool is operated during the driving-in of a nail, and thereby the likelihood of nails being jammed in the hammering tools is minimized to a considerable degree. The feeding mechanisms also are constructed with provision for periodically rotating the nail conveying tubes during the feeding of nails therethrough, so that the likelihood of jams occurring within the tubes is minimized.

Either hammering tool may be operated independently of the other or the tools may be operated simultaneously without difliculty. The hammering of the nails is so controlled that when a nail is driven home to a predetermined desired depth, the hammering automatically ceases without attention on the part of an operator, thereby not only assurin uniformity in the driving of the nails but indicating to a user when the nail has been driven home. Also, the sequence of automatic operations controlled by the movement of the trigger is such as to conserv time, since both the depressing and releasing movements of the trigger are utilized, and after the trigger has been released the tool is immediately ready for a subsequent nailing operation without waiting for transference of a new nail into position, or waiting for the feeding of a replacement nail to th tool.

The nails are fed to the hammering tools with a positive action, and therefore the operation of the machine is positive and reliable. The hammering tools are so arranged that during the initial period when a nail is being driven into the work at the time that a great part of the shank still remains outside of the work, the shank is supported so that the likelihood of its becoming bent during the driving operation is minimized to a considerabl degree.

Referring to the modification illustrated in Fig. 19, the muzzle portion ills of a hammering tool is shown, having a pair of pivotally mounted jaws 316 and 3| 1 which are spring urged together, and which have grooves 3| 8 cooperating to form a split channel through which the nail shank extends, and by which it is held, when the nail is being driven. The grooves 3l8 have tapering enlarged portions 319 to form a mouth or entrance for the nail heads, the latter spreading the jaws when passing therethrough.

Thus, a further support for the shanks of the nails 43 is provided, located closely adjacent the work, this support further preventing shifting of the hammering tool when the nails are being driven and the heads of the latter have spread apart the jaws I25 and I26.

Variations and modifications may be made within the scope of this invention and portions of the improvements may be used without others.

I claim:

1. Nailing apparatus comprising a nail hopper; a portable automatic hammer; means for operating the hammer; a flexible nail feed tube for transferring nails from the hopper to the hammer; electrically operated means movable through a predetermined cycle for feeding the nails along said tube; and means including a manually operable member carried by the hammer, for controlling the operation of the hammer, said means also initiating the cycle of said electrically operated means for feeding nails thereto whereby for each nail driven by the hammer a nail is transferred from the feed tube to reload the hammer.

2. Nailing apparatus comprising a nail hopper; a portable automatic hammer; means for operating the hammer; a flexible nail feed tube for transferring nails from the hopper to the hammer; electrically operated means acting through a cycle for feeding a nail from the feed tube to reload the hammer; and means including a manually operable member carried by the hammer, for controlling the operation of the hammer, said means also actuating the said electrically operated means for feeding nails thereto whereby for each actuation of the member to operate the hammer to drive a nail fully into the work, one nail only is transferred from the feed tube to reload the hammer.

3. Nailing apparatus comprising a hopper; a nail conveying tube; means for depositing nails one at a time into the nail conveying tube; means for intermittently advancing a succession of the nails along the tube to the delivery end thereof; a drum having a plurality of chambers successively aligned with the delivery end of the tube, the nails being transferred one at a time from the tube to the drum; nail driving means including a hammer aligned with a chamber of said drum containing a nail for driving the nail into the work, said means also including means for automatically reciprocating the hammer to cause it to repeatedly strike the nail until it is driven to the desired depth; a fingerpiece for controlling the operation of the hammer; means operated by the fingerpiece for controlling operation of the nail advancing and depositing means at each operation of the fingerpiece; and means for rotating the drum step by step at each operation of the fingerpiece to move an empty chamber into alignment with the nail conveying tube and a loaded chamber into alignment with the hammer, said last-named means operating on the return movement of the fingerpiece.

4. Nailing apparatus comprising a hopper; a nail conveying tube; means for depositing nails one at a time into the nail conveying tube; means for intermittently advancing a succession of the nails in end-to-end relation along the tube to the delivery end thereof; a hammer for driving the nails; and means for transferring the nails in the tube one by one to position to be driven into the work by the hammer.

Nailing apparatus comprising a nail hopper; a portable automatic hammer; means for operating the hammer; a flexible nail feed tube for transferring a succession of nails from the hopper to the hammer; means separate from the hammer operating means and operable through a cycle independently of the operation of said hammer for advancing the nails in the feed tube;

and manually operable means carried by the hammer for controlling the operation of the latter, said means being connected to the separate operating means to control the nail-advance means whereby for each nail driven by the hammer the nails in the feed tube are advanced by one nail, thereby to reload the hammer.

6. Nailing apparatus comprising a nail hopper; nail feed means leading from the hopper; means for placing nails one at a time into the feed means; means acting on the nails for intermittently advancing a succession of nails in end-toend relation along the feed means to the delivery end thereof; a hammer for driving the nails; and means for transferring the nails at the delivery end of the feed means one by one into osition to be driven by the hammer into the work.

7 Nailing apparatus comprising a nail hopper; nail feed means leading from the hopper and carrying a succession of nails therein in end-to-end relation; means for placing nails one at a time into the feed means in end-to-end relation; a nail transfer and supporting device located adjacent the delivery end of the feed means, for receiving nails one by one from the latter, and for transferring the nails in progression to a driving station and supporting the same therea-t; a harm mer at said driving station; and means for reciprocating the hammer to drive the nails into the work.

8. Nailing apparatus comprising a hopper; a flexible nail conveying tube; means for depositing nails one at a time from the hopper into the nail conveying tube; means for advancing a succession of the nails along the tube to the delivery end thereof; a rotatable nail transfer device having a plurality of means for supporting nails in squirrel-cage arrangement about its axis, said nail supporting means being successively presented to the delivery end of the conveying tube by rotation of the transfer device, to receive nails 24 from the said tube; a hammer associated with the transfer device at a driving station, for driving the nails into the work, said nail supporting means being presented successively to the driving station by rotation of the transfer device; means for automatically reciprocating the hammer to cause it to repeatedly strike a hall at the driving station, said means including a fingerpiece for controlling the operation of the hammer; and means operated by the fingerpiece for rotating the nail transfer device and for controlling the means advancing the nails in the conveying tube whereby for each cycle of operation of the fingerpiece a nail is positioned in the transfer device and the latter rotated so as to bring a nail to the driving station, said transfer device rotating on the return movement of the fingerpiece.

9. In a nailing apparatus, nail feed means comprising a hopper; a flexible nail feed tube for transferring nails from the hopper to a portable hammer; means for placing nails one at a time into the feed tube to provide a succession of nails in end-to-end relation; and means acting on the nails in the tube for advancing the nails in the feed tube, said last-named means acting in predetermined sequence with the placing of nails therein.

10. In a nailing apparatus, nail feed means comprising a hopper; 'a flexible nail feed tube for transferring nails from the hopper to a portable hammer; means for placing nails one at a time into the feed tube; and means for advancing the nails in the feed tube, including means for rotating the tube during the advance of nails therein to prevent jamming.

11. In a nailing apparatus, nail feed means comprising a hopper; a nail magazine tube connected with the hopper; means for filling the magazine tube with nails from the hopper, and for maintaining said tube filled; a flexible nail conveying tube associated with the magazine tube and connected with a portable hammer; means for transferring nails one at a time from the magazine tube to the conveying tube; and means for advancing the nails in the conveying tube in predetermined sequence with the transferring of nails thereto, including means for rotating the conveying tube during the advance of the nails to prevent jamming.

12. In a nailing apparatus, nail feed means comprising a hopper; a pair of nail magazines connected to the hopper; a pair of flexible nail feed tubes connected respectively with the magazines; means for loading the magazines with nails from the hopper; means for feeding the nails one at a time from the magazines respectively to the flexible feed tubes with the nails in end-to-end relation; and means acting upon the nails in the tube for advancing the nails in each of the feed tubes in predetermined sequence with the loading of the nails therein.

13. A portable nailing machine comprising a hammer mounted for reciprocative movement; a nail magazine; a manually operable trigger;

- means operable through a predetermined cycle upon actuation of said trigger for removing nails successively from the magazine and supporting the nails in front of the hammer; and a second means separate from the first means and under the control of the trigger and operative after operation of said first-named means for reciprocating the hammer to cause the latter to strike a supported nail repeated blows and drive the same into the work.

14. A portable nailing machine comprising a hammer mounted for reciprocative movement; a nail magazine; a manually operable trigger; means operable through a predetermined cycle upon actuation of said trigger for removing nails successively from the magazine and supporting the nails in front of the hammer; a second means separate from the first means and under the control of the trigger and operative after operation of said first-named means for reciprocating the hammer to cause the latter to strike a supported nail repeated blows and drive the same into the work; and means controlled by the trigger and operative after said second-named means for moving the hammer to a retracted starting position and maintaining the latter therein when the trigger is released.

15. A portable nailing machine comprising a nail receiver; a hammer mounted for reciprocative movement with respect to the receiver, to drive a nail held by the receiver from the latter into the work; a manually operable trigger; fluid operated means under control of the trigger for reciprocating the hammer to cause the latter to strike the nail repeated blows; and means controlled by the trigger for moving the hammer to a retracted starting position and maintaining the latter therein when the trigger is released, so that another nail may be positioned by the receiver for driving by the hammer.

16. A portable nailing machine comprising a hammer mounted for reciprocative movement; a nail magazine; a manually operable trigger; means under the control of the trigger for removing nails successively from the magazine and supporting the nails in front of the hammer; means under the control of the trigger and operative after operation of said first-named means for reciprocating the hammer to cause the latter to strike a supported nail repeated blows and drive the same into the Work; and means controlled by the trigger and operative after said second-named means for moving the hammer to a retracted starting position and maintaining the latter therein when the trigger is released, said first-named means operating after operation of the said last-named means, and in response to release of the trigger.

1'7. A portable nailing machine comprising a rotatable nail carrying member having means for supporting a plurality of nails in squirrelcage arrangement about its axis; means for imparting a stepped rotary movement to the member to move the nails to a discharge station; magazine means for supplying nails; means for feeding a nail supplied by the magazine means into each successive supporting means of the member at a loading station during the periods the member is motionless; means for driving the nails successively from the supporting means of the member at a discharge station during the said periods, said nail supporting means including guide means to surround the shank of the nail and expand to permit passage of the head of the nail when the latter is driven from the member at the discharge station; and means for maintaining the guide means expanded after the initial expansion, for the duration of the operation of the drive means.

18. A portable nailing machine comprising a rotatable nail carrying member having means for supporting a plurality of nails in squirrel-cage arrangement about its axis; means for imparting a stepped rotary movement to the member to move the nails to a discharge station; a nail supplying tube adapted to carry a plurality Of nails 26 point-to-head one after another to said member; means for feeding the nails one at a time from the tube to the nail carrying member at a loading station during the periods the member is motion less; and means for driving the nails carried by the member successively from the latter at a discharge station during the said periods.

19. A portable nailing machine comprising a rotatable nail carrying member having means for successively supporting a plurality of nails in squirrel-cage arrangement about its axis; maga-v zine means for supplying nails; means for feeding a nail supplied by the magazine means into each successive supporting means of the member at a loading station; a hammer aligning with one of the nail supporting means of the member at a discharge station; manually operable means; means actuated by the manually operable means for controlling the operation of the hammer; and separate means also actuated by said manually operable means for advancing the member a step at a time to bring successive nail supporting means of the member to the loading and discharge stations respectively.

20. A portable nailin machine comprisinga rotatable nail carrying member having means for supporting a plurality of. nails in squirrelcage arrangement about its axis; nail feed means associated with the member at a loading station to supply nails to said member; means for driving a nail, associated with the member at a discharge station; manually operable means for controlling the operation of the nail driving means; and separately controlled means actuated by the manually operable means for imparting a stepped rotary movement to the member, including means for advancing the nails in the feedmeans one at a time to the nail sup-f porting means of'the member during the periods that the latter is motionless. 7

21. A portable nailin machine comprising a drum having nail receiving and carrying chambers; a nail supply tube aligning with one of the chambers which receives a nail from the tube; a hammer aligning with one of the chambers carrying a nail; manually operable means; means actuated by the manually operable means for controlling the operation of the hammer; and separately controlled means also actuated by said manually operable means for advancing the drum to move an empty chamber into alignment with the tube and a nail loaded chamber into alignment with the hammer.

22. A portable nailing machine comprising a drum having nail receiving and carrying chambers; a magazine tube aligning with an empty one of the chambers which receives a nail from the tube; a hammer aligning with one of the chambers carrying a nail; manually operable means for controlling the operation of the hammer; means controlled by said manually operable means for advancing the drum to move an empty chamber into alignment with the magazine tube and a nail loaded chamber into alignment with the hammer; and means controlled by the manually operable means for advancing the nails one at a time from the magazine tube to the aligned chamber.

23. A portable nailing machine comprising a drum having nail receiving and carrying chambers; a magazine tube aligning with an empty one of the chambers which receives a nail from the tube; a hammer aligning with one of the chambers carrying a nail; manually operable means for controlling the operation of the ham- 27 mer; and means controlled by the manually operable means for advancing the nails one at a time from the magazine tube to the aligned chamber.

24. A portable nailing machine comprising a drum having nail receiving and carrying chambers; a magazine tube aligning with one of the chambers to receive nails from the tube; a hammer aligning with one of the chambers carryin a nail; means for reciprocating the hammer to drive a nail; manually operable means for controlling the operation of the hammer; means controlled by said manually operable means for advancing the drum to move an empty chamber into alignment with the magazine tube and a nail loaded chamber into alignment with the hammer; and guide means in each of said chambers to surround the shank of the nail to hold the nail during repeated blows by the hammer and expand to permit passage of the head of the nail after the nail has been driven a predetermined distance by the hammer.

25. A portable nailing machine comprising a drum having nail receiving and carrying chambers; a magazine tube alignin with one of the chambers to receive nails from the tube; a hammer aligning with one of the chambers carrying a nail; means for reciprocating the hammer to drive a nail; manually operable means for controlling the operation of the hammer; means controlled by said manually operable means for advancing the drum to move an empty chamber into alignment with the magazine tube and a nail loaded chamber into alignment with the hammer; guide means in each of said chambers to surround the shank of the nail to hold the nail during repeated blows by the hammer and expand to permit passage of the head of the nail after the nail has been driven a predetermined distance by the hammer; and means for holding said guide means expanded until the drum is again advanced.

26. A portable nailing machine comprising a drum having nail receiving and carrying chambers; a nail supply tube for supplying nails to the chambers; a hammer aligning with one of the chambers carrying a nail; means for reciprocating the hammer to drive a nail; manually operable means for controlling the operation of the hammer; means controlled by said manually operable means for advancing the drum to move an empty chamber into alignment with the tube and a nail loaded chamber into alignment with the hammer; a split guide for the nails in each chamber, adapted to be opened to permit passage of the head of the nail when struck by repeated blows of the hammer; and a wedge for holding the guide open during the final driving of the nail and until the drum is again advanced.

27. In a portable power-driven hammering tool, a casing; a hammer mounted in the casing for reciprocative movement; means for driving the hammer with a varyingstroke as the nail is driven in; means for positioning a nail in front of the hammer to be driven by the latter into a workpiece; and means for rendering said hammer driving means inoperative when the hammer stroke has increased a predetermined amount in driving the nail into the workpiece.

28. A portable nailing machine comprising a casing; a hammer mounted in the casing for reciprocative movement; means for positioning a nail in front of the hammer, to be driven by the latter out of the casing and into the work; means, including a manually operable member, for automatically reciprocating the hammer with a varying stroke as the nail is driven in when the member is depressed; means for rendering inoperative the hammer reciprocating means when the stroke of the hammer, in driving the nail, has increased a predetermined amount; and means for returning the hammer to starting position when the manually operable member is released.

29. Nailin apparatus comprising a hammering tool, a manual actuator for controlling the operation thereof, a nail supply feeding means including instrumentalities for transferringthe nails from the supply to the tool, electrically operated means for operating said instrumentalities in a cycle to feed a nail from the supply to the tool, the circuit thereto being closed and said electrically operated means being rendered operative for a complete cycle by each actuation of the manual actuator.

ROCCO PAPALIA.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 331,299 Hopkins Dec. 1, 1885 418,697 Dean Jan. 7, 1890 429,527 Hyslop, Jr June 3, 1890 902,620 Stewart Nov. 3, 1908 908,921 Whitcomb Jan. 5, 19.09 958,002 Phelan May 17, 1910 1,014,639 Colwell Jan. 16, 1912 1,420,318 Keller June 20, 1922 1,703,458 Ruff Feb. 26, 1929 1,847,275 Standish Mar. 1, 1932 1,888,520 Twomley Nov. 22, 1932 1,980,967 De Mooy Nov. 13, 1934 1,984,117 Davis Dec. 11, 1934 2,059,708 Roth Nov. 3, 1936 2,088,761 Roberts Aug. 3, 1937 2,120,992 Seiden June 21, 1938 2,171,946 Palmros Sept. 5, 1939 2,283,047 Colestock May 12, 1942 2,310,638 Hubbard Feb. 9, 1943 2,400,330 Allen May 14, 1946 Certificate of Correction Patent No. 2,498,503 February 21, 1950 ROCCO PAPALIA It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows:

Column 6, line 6, strike out the word is after the numeral 33; column 7, line 46, for integra read internal; column 10, line 73, for nozzle read muzzle;

and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 4th day of July, A. D. 1950.

THOMAS F. MURPHY,

Assistant Uommz'asioner of Patents. 

